The lightning strike of an aircraft in flight is not a rare phenomenon. It is estimated that strikes on civilian transport planes amount to about one strike per plane per year. The current trend in aeronautical engineering is to use lighter weight materials, fewer mechanical systems and more electronic systems. Electronic systems are often more sensitive than mechanical systems to electromagnetic disturbances such as those generated by lightning. Recently, electrically non-conductive or partially conductive fiber reinforced resin matrix materials are being used to fabricate more parts for airplanes, as well as for wind generators, automobiles, sporting goods, furniture, buses, trucks and other applications where stiff, light-weight materials, or consolidation of parts are beneficial. These lighter weight structures offer less effective protection against lightning than the traditional aluminum structures.
Conditions at the lightning attachment site are extreme. For lightning attachments to aircraft, electrical current transients as high as 200,000 amperes are expected with charge transfers exceeding 200 coulombs. (SAE ARP5412 Revision A, Aircraft Lightning Environment and Related Test Waveforms, SAE International, 1 Nov. 1999.) Lightning attachments to wind generators vary greatly by geographic location and height, but electrical current transients as high as 100,000 amperes are expected with charge transfers as high as 300 coulomb. (Technical Report 61400-24, Wind Turbine Generator Systems—Part 24: Lightning Protection, International Electrotechnical Commission, 1st edition 2002-07.) The temperature of the plasma in the lightning strike column has been estimated to be about 28,000°K. (“A numerical modeling of an electric arc and its interaction with the anode: part III. Application to the interaction of a lightning strike and an aircraft in flight,” F Lago, J J Gonzalez, P Freton, F Uhlig, N Lucius and G P Piau 2006 J. Phys. D: Appl. Phys. 39 2294-2310.) Much of the damage caused by a lightning strike is the result from extreme levels of heat at the strike location caused by the elevated temperature within the lightning arc and ohmic heating of the materials.
Some investigators report the use of lightning protection systems which include conductive layers such as metalized woven fabric, metalized paper, solid metal films, foraminous metal films, metal wires, metal mesh, metal particles, expanded metal foils, carbon particles or carbon fibers. Some investigators report the use of lightning protection systems which include ionizable outer layers, such as paint layers. Strikes frequently destroy the protection mechanism at the attachment sites and cause measureable damage to modern light weight structures. This necessitates costly structural repair and related service interruption. The following references may be relevant to such technologies: WO 2005/032812 A, US 2006/051592 A1, WO 2007/048426 A, US 2008/142238 A1, US 2004/0069895, U.S. Pat. No. 4,920,163, EP 0227122 A, U.S. Pat. No. 7,277,266 B1, US 2007/0236855 A1, WO 2007/123700 A1, US 2007/0230085 A1, EP 1,935,784 A2, WO 2008/040936 A1, U.S. Pat. No. 4,352,142, WO2008/076851 A1, US 2007/0141927 A1, US 2008/0145555 A1, EP 1,944,236 A2, US 2008/0170349 A1, FR 2,720,214 A1, US 2007/0258182 A1, US 2007/0093163 A1, US 2007/0201179 A1, U.S. Pat. Nos. 5,127,601, 3,989,984, WO 2008/015082 A1, WO 2008/006377 A1, WO 2008/046186 A1, WO 2007/142354 A1, WO 2008/048705 A2, WO 2008/056123 A1, EP 1,935,631 A3, RU 2,263,581, RU 2,217,320 C1, WO 2002/076430 A, RU 2,192,991 C, EP 1,011,182 A1, EP 0,900,647 A, EP 629,549 A, DE 10 2006 046 002 B4, EP 163,805 A1, U.S. Pat. Nos. 5,132,168 A, 3,755,713 A and US 2006/0143920 A1.